On a wet Friday in May the four of us travelled with Mrs Campbell, our teacher to Birkdale on the Upper Harbour. Mrs Mumme has lived on Hellyer’s Creek for 50 years so she could tell us a lot about how the mangroves were taking over the creek which is an historic waterway.

We had first heard of Marjorie Mumme when we read an article in our local paper, the North Shore Times, November 27, 2007. The headline read, “Mangroves – they must go!”

“Nearby Herald Island actually gets its name from a sailing ship of that name that used to sail up the waterway to the freshwater lagoon at the top. They got fresh water from the waterfall there.”

She showed us a map of the area, drawn by her husband when he was a boy. It showed where the mangroves were over 50 years ago.

After feeding us fruit juice and delicious biscuits, we set off along the chain reserve beside Hellyer’s Creek to discover how many mangroves were there now.

“We must keep the waterways clear,” she said, pointing to large trees that had fallen.

“Trees that fall in stop the water flowing. They trap the mud and encourage mangroves to take root.”

We were amazed how the mangroves had spread so much and how Shoal Bay’s mangroves seemed more controlled. In some places we could not even see the water.

“Mangroves are not a rubbish dump either!” We were shocked to see people had used the mangroves to throw away their rubbish.

“I remember when people used to yacht here or fish in the creek. All the godwits have gone too,” she went on. “Mangroves are the gorse of the sea!”

Her submission suggests that mud and cement should be mixed to make walls along the creek and stop silt closing it up.

Mrs Mumme says she needs more help because she is getting too old for this.

We realised that young people like us need to make a difference. We need to find good ways to get rid of mangroves that are growing in the wrong place, but we need to save the environment too.